Choral Public Domain Library

I have been making text/translation/underlay improvements and adding source attribution in several editions. I can upload the new PDF files without a problem, but sometimes, not always, my new MXL files are rejected as being identical to the old files. The files are slightly different, however. Is there a remedy??
Thank you for your help.
-----Jim Pearson

When a user uploads a file with same file name as an already existing file, and which content is identical, I think the system does... nothing and do not deliver any error message.
When a user uploads a file with same file name as an already existing file, but which content is different, two cases:
- if the uploading user is the same as at last upload (or an admin), a warning about overwriting the previous version is shown, but overwriting is allowed;
- if the uploading user is not the same, I think overwriting is forbidden.

Does it make a difference how one navigates to the special upload file page? One way of course is to use Tools/Upload file. But if I look at https://www.cpdl.org/wiki/index.php/Fil ... isroel.mxl there's a "Upload a new version of this file" button that should preserve a file history.